scripts/unit-test.py: Dump the test log if tests fail
scripts/unit-test.py: Dump the test log if tests fail

Also clean up the redundant handling of the make invocation. If we want
to control make's behaviour, set MAKEFLAGS when calling the script.

Tested: Ran run-unit-test-docker.sh, confirmed log dump on test failure

Change-Id: Ibbc58a2ccfbe92c2e80db82a9ed91a61c7496131
Signed-off-by: Andrew Jeffery <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@aj.id.au>

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts